Electronic brake system using integrated sensor and method of operating the same

ABSTRACT

Disclosed herein is an electronic brake system using an integrated sensor, which includes a hydraulic block configured to distribute and supply a fluid to a wheel brake, and having a through-hole penetrated at both sides thereof, a sensor module installed at one side of the hydraulic block having the through-hole, for sensing a linear displacement of a brake pedal and a position of a motor, and an electronic control unit installed to a side of the hydraulic block opposite to the sensor module, in order to determine a movement distance of the pedal, based on the linear displacement of the pedal sensed by the sensor module, and control rotation of the motor depending on the linear displacement of the pedal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No.10-2015-0037597, filed on Mar. 18, 2015, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND

The technology disclosed in this patent document relates to automobilebrakes.

Brake boosters can be used to increase braking efficiency and improveresponse speed during braking in automobiles, such as hybrid andelectric vehicles. Some existing electronic brake systems having brakeboosters are mounted in vehicles serve to increase braking efficiencyand improve response speed during braking described above. In addition,the electronic brake systems may reduce costs by integrating elementsrelated to braking functions. Electronic brake systems can embodyvarious desired functions related to vehicle safety.

SUMMARY

Exemplary embodiments of the disclosed technology relate to anon-contact integrated sensor module applied to a vehicle electronicbrake system, and more particularly, to a structure in which a singlehousing is provided with a pedal displacement sensor and a rotorposition sensor for controlling an electric motor according to avariation in pedal displacement.

The disclosed technology can be used or implemented in one or more waysto provide a sensor unit in which a pedal displacement sensor integrateswith a motor rotor displacement sensor, and more particularly, toprovide a stable electronic brake system in which a non-contact linearposition sensor and a non-contact rotational position sensor are mountedas a single integrated sensor module.

In accordance with one aspect of the disclosed technology, an electronicbrake system using an integrated sensor includes a hydraulic blockconfigured to distribute and supply a fluid to a wheel brake, and havinga through-hole penetrated at both sides thereof, a sensor moduleinstalled at one side of the hydraulic block having the through-hole,for sensing a linear displacement of a brake pedal and a position of amotor, and an electronic control unit installed to a side of thehydraulic block opposite to the sensor module, in order to determine amovement distance of the pedal, based on the linear displacement of thepedal sensed by the sensor module, and control rotation of the motordepending on the linear displacement of the pedal.

The sensor module may include a sensor housing coupled to thethrough-hole of the hydraulic block, and having a through-holepenetrated at both sides thereof, a circuit board installed at one sideof the sensor housing and having a through-hole penetrated at both sidesthereof, a sensing-related electric part being mounted on the circuitboard, a pedal sensor module mounted at one side of the circuit board,in order to sense a magnetic field variation depending on movement ofthe pedal, and transfer information about the sensed magnetic fieldvariation to the electronic control unit, and a motor sensor modulemounted at one side of the circuit board, in order to sense an inducedcurrent generated by rotation of a rotor, and transfer information aboutthe sensed induced current to the electronic control unit.

The electronic brake system may further include a connection unitelectrically connecting the sensor module to the electronic control unitthrough the through-hole of the hydraulic block while one end of theconnection unit is fixed to the sensor module.

The pedal sensor module may include an input rod connected to theconnection unit so as to be moved depending on movement of the pedal, amagnet provided at one end of the input rod so as to be moved dependingon movement of the input rod, and a sensor unit configured to sense amagnetic field variation depending on movement of a magnetic substance,and transfer the sensed magnetic field variation to the electroniccontrol unit.

The sensor unit may be installed at one side of the circuit board, andthe magnet may be disposed above the sensor unit so as to be spacedapart from the sensor unit.

The sensor unit may be one of a Hall device, a reed switch, an AMR(Anisotropic Magneto-Resistive) sensor, and a GMR (GiantMagneto-Resistive) sensor.

The sensor unit may respond to a magnetic field having a directionalcomponent in an x-z plane or a y-z plane perpendicular to the circuitboard to sense a variation of the magnetic field, and the electroniccontrol unit may generate an x-z angle signal or a y-z angle signalindicative of an angle of the directional component of the magneticfield from information about the variation of the magnetic field.

The motor sensor module may include a coil in which an induced currentis generated by movement of the motor rotor, and a current sensorconfigured to sense the induced current in the coil and transfer a valueof the sensed induced current to the electronic control unit.

The coil may include a first coil in which a magnetic flux is formed byelectric energy generated by rotation of the motor, and a second coilconfigured of a pair of coils connected to each other while an inducedcurrent is generated according to the magnetic flux in the first coil.

The electronic control unit may determine an rpm of the motor, based ona rotation angle displacement of the motor.

In accordance with another aspect of the disclosed technology, a methodof operating an electronic brake system, including a circuit boardconfigured such that a pedal sensor module for sensing a lineardisplacement of a pedal is mounted on one side of the circuit board anda motor sensor module for sensing a rotation angle displacement of amotor is mounted on the circuit board, using an integrated sensor,includes sensing a variation of a magnetic field generated by a magnetmoved along with movement of an input rod, determining a movementdistance of the pedal, based on an intensity and a direction of themagnetic field, sensing a position of the motor, and controllingrotation of the motor corresponding to the movement distance of thepedal.

The method may further include determining a rotation displacement ofthe motor, based on the rotation of the motor.

The method may further include responding to a magnetic field having adirectional component in an x-z plane or a y-z plane perpendicular tothe circuit board to sense a variation of the magnetic field, andgenerating an x-z angle signal or a y-z angle signal indicative of anangle of the directional component of the magnetic field frominformation about the variation of the magnetic field.

It is to be understood that both the foregoing and the followingdetailed descriptions are exemplary and explanatory.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features and advantages of the disclosed technology are furtherdisclosed in the following detailed description taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a view illustrating an electronic brake system according to anembodiment of the disclosed technology;

FIG. 2 is a perspective view illustrating the electronic brake system ofFIG. 1;

FIG. 3 is an exploded perspective illustrating a sensor module accordingto the embodiment of the disclosed technology;

FIG. 4 is a front view illustrating the coupled structure of the sensormodule in the electronic brake system of FIG. 1;

FIG. 5 is a rear view illustrating the coupled structure of the sensormodule in the electronic brake system of FIG. 1; and

FIG. 6 is a flowchart illustrating a method of operating an electronicbrake system according to an embodiment of the disclosed technology.

DESCRIPTION OF SPECIFIC EMBODIMENTS

In general, electronic brake systems are aimed at obtaining strong andstable braking force by efficiently preventing vehicles from slipping.For the electronic brake systems, there are designs based on anAnti-Lock Brake System (ABS) which prevents wheels from slipping when avehicle is braked, a brake traction control system which prevents drivewheels from slipping when a vehicle speeds up or suddenly accelerates,and a vehicle attitude control system which stably maintains travelingof a vehicle by controlling brake oil pressure through the combinationof an ABS and a brake traction control system.

Such an electronic brake system includes a plurality of solenoid valvesfor adjusting braking hydraulic pressure transferred to a wheel brake, ahydraulic block mounted with low-pressure and high-pressureaccumulators, and an electronic control unit for controlling the drivingof the solenoid valves and motor.

In various conventional electronic brake systems, an electronic brakesystem can be individually provided with a pedal displacement sensor anda motor rotor displacement sensor, and leads for transmission ofelectric signals indicative of displacements have long lengths due tothese two individual sensors. Due to those features, the whole responsespeed of the brake system may be lowered.

In addition, the structures of the pedal displacement sensor and themotor rotor displacement sensor may produce a undesired influence on thesurrounding environment of the brake system, and may increase theconstituent components of the brake system. Accordingly, an assemblytime may be increased, system safety may be lowered, and costs may beincreased.

Exemplary embodiments of the disclosed technology are described below inmore detail with reference to the accompanying drawings. Throughout thedisclosure, like reference numerals refer to like parts throughout thevarious figures and embodiments. In certain embodiments, detaileddescriptions of device constructions or processes well known in the artmay be omitted to avoid obscuring appreciation of the disclosure by aperson of ordinary skill in the art.

The disclosed technology may be embodied in different forms and specificexamples disclosed in this document should not be construed aslimitations to implementations of the disclosed technology.

In the context of this document, the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof

As illustrated in FIGS. 1 to 5, the electronic brake system according tothe embodiment of the disclosed technology is an electronic brake systemusing an integrated sensor, which has a separate fluid supply unit forsupplying a fluid. The electronic brake system may include a hydraulicblock 200 which is configured to distribute and supply a fluid to awheel brake, and has a through-hole 201 penetrated at both sidesthereof, a sensor module 130, which is installed at one side of thehydraulic block 200 having the through-hole 201, and senses a lineardisplacement of a brake pedal and a position of a motor, and an ECU(Electronic Control Unit) 300 which is installed to the side of thehydraulic block 200 opposite to the sensor module 130, determines amovement distance of the pedal, based on the linear displacement of thepedal sensed by the sensor module 130, and controls rotation of themotor depending on the linear displacement of the pedal.

FIG. 3 is an exploded perspective illustrating the configuration of thesensor module 130 according to the embodiment of disclosed technology.

The sensor module 130 may include a sensor housing 110 which is coupledto the through-hole 201 of the hydraulic block 200, and has athrough-hole 202 penetrated at both sides thereof, a circuit board 120which is installed at one side of the sensor housing 110, has athrough-hole 203 penetrated at both sides thereof, and is mounted with asensing-related electric part, a pedal sensor module which is mounted atone side of the circuit board 120, senses a magnetic field variationdepending on movement of the pedal, and transfers information about thesensed magnetic field variation to the ECU 300, and a motor sensormodule which is mounted at one side of the circuit board 120, senses aninduced current generated by rotation of a rotor, and transfersinformation about the sensed induced current to the ECU 300.

In addition, the electronic brake system may further include aconnection unit which electrically connects the sensor module 130 to theECU 300 through the through-hole 201 of the hydraulic block 200 whileone end of the connection unit is fixed to the sensor module 130.

The pedal sensor module may include an input rod 131 which is connectedto the connection unit, and is moved depending on movement of the pedal,a magnet 133 which is provided at one end of the input rod 131, and ismoved depending on movement of the input rod 131, and a sensor unit 135which senses a magnetic field variation depending on movement of amagnetic substance, and transfers the sensed magnetic field variation tothe ECU 300.

In this case, the sensor unit 135 may be installed at one side of thecircuit board 120, and the magnet 133 may be disposed above the sensorunit 135 so as to be spaced apart from the sensor unit 135.

Here, the sensor unit 135 may be any one of a Hall device, a reedswitch, an AMR (Anisotropic Magneto-Resistive) sensor, and a GMR (GiantMagneto-Resistive) sensor.

In addition, the sensor unit 135 responds to a magnetic field having adirectional component in the x-z plane or y-z plane perpendicular to thecircuit board 120 to sense a variation of the magnetic field, and theECU 300 may generate an x-z angle signal or a y-z angle signalindicative of the angle of the directional component of the magneticfield from information about the variation of the magnetic field.

The motor sensor module may include a coil in which an induced currentis generated by movement of a motor rotor 43, and a current sensor whichsenses the induced current in the coil and transfers a value of thesensed induced current to the ECU 300.

The coil may include a first coil in which a magnetic flux is formed byelectric energy generated by rotation of the motor, and a second coilconfigured of a pair of coils connected to each other while an inducedcurrent is generated according to the magnetic flux in the first coil.

The ECU 300 may determine an rpm of the motor, based on the rotationangle displacement of the motor.

Hereinafter, the operation of the electronic brake system using anintegrated sensor according to the embodiment of the disclosedtechnology will be described.

The hydraulic block 200 may be provided with a passage constituting ahydraulic circuit which is connected to a master cylinder to adjust thepressure of brake oil transferred to wheel brakes installed at front andrear wheels, so that the introduced brake oil is discharged to the wheelbrakes through the hydraulic circuit.

The ECU 300 is a unit which controls an electronic brake, based onsensing values required to control the brake, and is coupled to onesurface of the hydraulic block 200 by a fastening member.

The ECU 300 includes a separate housing, and the housing may beinstalled to the hydraulic block 200 by a fastening member.

The ECU 300 may refer to an electronic control device which controls thestates of a vehicle engine, an automatic transmission, an ABS, etc.using a computer, and may generally control the electronic brake systemof the disclosed technology.

The sensor module 130 is coupled to the side of the hydraulic block 200opposite to the ECU 300, and may be connected to the ECU 300 by aseparate connection unit to be described below.

The sensor module 130 according to the embodiment of the disclosedtechnology may sense the position of the motor, and simultaneously sensethe linear displacement of the pedal.

That is, by integrating two sensors, which sense positions of differentparts, as a single module, it is possible to improve the safety of theelectronic brake system, simplify the structure of the electronic brakesystem, and reduce costs. In addition, since a space required to mountsensors is reduced, it is possible to increase the utilization of space.

The sensor module 130 may include a motor sensor module which senses theposition of the motor, and a pedal sensor module which senses a magneticfield variation depending on movement of the pedal. That is, the sensormodule 130 may include a structure in which two individual non-contactsensors are mounted on one circuit board 120.

That is, the main constituent components of the module are included in asingle structure.

The pedal sensor module is to sense the displacement of the brake pedal.The pedal sensor module may sense a variation and intensity of magneticfield depending on the input rod 131 moved when a driver presses thebrake pedal.

Referring to FIG. 5, the circuit board 120 mounted with the pedal sensormodule may be seen.

In more detail, the magnet 133 connected to one end of the input rod 131is moved along with the movement of the input rod 131 connected to thepedal. A magnetic field is generated by the movement of the magnet 133,and the sensor unit 135 may sense a variation of the magnetic field.

In addition, values indicative of the direction and intensity of themagnetic field sensed by the sensor unit are transferred to the ECU 300,and the ECU 300 may determine a displacement of the input rod 131, i.e.a level of the pedal pressed by the driver, based on the values.

Here, the sensor unit 135 may use a Hall sensor or an induced currentsensor, or use any one of a reed switch, an AMR sensor, and a GMRsensor.

The sensor unit 135 may respond to a magnetic field, which is generatedby movement of the magnet 133 and has a directional component in the x-zplane or y-z plane, to sense a variation of the magnetic field. Thedirectional component may be output as a linear value deduced byconverting a sine or cosine value into an arctangent value. The outputlinear value may be transferred to the ECU 300.

The sensor unit 135 may include a plurality of magnetic sensors. In thiscase, the sensor unit 135 may be set to receive a representative signalof signals output from the magnetic sensors. In addition, the sensorunit 135 may include an angle detection circuit configured to generatean x-z angle signal indicative of the directional component of themagnetic field in the x-z plane, and an angle detection circuitconfigured to generate a y-z angle signal indicative of the directionalcomponent of the magnetic field in the y-z plane.

In some examples of the sensor unit 135, a plurality of magnetic sensorelements may include a plurality of vertical Hall elements arranged inthe form of circular vertical Hall.

In some examples of the sensor unit 135, the vertical Hall elements andthe angle detection circuits may be connected to a single circuit board120.

In some examples of the magnetic sensor, a plurality of magnetic sensorelements may include a plurality of magnetoresistances.

The motor sensor module is to sense the position of the motor, and maysense the absolute position of the motor such that the motor may bedriven according to the variation of the pedal. That is, the motorsensor module may sense the position of the motor such that electricpower may be applied to the motor for actuation thereof

The motor sensor module may integrally detect the position of the motorthrough a variation in magnetic field caused by the magnet for detectingthe variation of the pedal, without using a separate magnet fordetecting the position of the motor.

In addition, the motor sensor module may use a first coil and two secondcoils in order to convert a displacement into an electric signal usingthe mutual induction action of coils by an LVDT (Linear VariableDifferential Transform).

The LVDT refers to an electric converter which measures a different inlinear distance, and has a structure in which three solenoid coils arelocated around a tube. Among the three solenoid coils, the main coil islocated at the center, and the remaining two coils are located aroundthe main coil. The LVDT informs of a position value of an object to bemeasured by moving a cylindrical magnet core along the center of thetube.

Referring to FIG. 4, the front portion of the brake system mounted withthe sensor module 130 according to the disclosed technology may be seen.In FIG. 4, the motor rotor 43 connected to the motor, the coil in whichan induced current is generated by the rotation of the motor rotor 43,and the circuit board 120 connected to the coil may be seen.

The circuit board 120 has a coil pattern, and thus an induced currentmay be generated by the rotation of the rotor which is rotated alongwith the rotation of the motor. The method of detecting the rotation ofthe motor through the induced current may use the LVDT.

The LVDT, which converts a mechanical displacement into an electricsignal, is a transducer which changes a variation of magnetic fluxinduced in a primary coil and a secondary coil according to movement ofa core or an armature, i.e. changes a mutual inductance. Here, themechanical displacement may be output as an electric signal inproportion to the displacement of the core which is movable in themechanically or electrically separated state. The LVDT may include aformer around which a coil is wound, a core, a support rod forsupporting the core, and a case.

The induced current measured through the coil is transferred to the ECU300, and the

ECU 300 may detect information related to an absolute position of themotor, an amount of rotation thereof, and a rotation direction thereof,based on the measured induced current.

Referring to FIG. 2, the connection unit, which electrically connectsthe sensor module 130 to the ECU 300, may be penetrated and coupled tothe hydraulic block 200 before the sensor module 130 is connected to theECU 300.

Accordingly, when the connection unit is decoupled from the sensormodule 130, the connection unit may be connected to the sensor module130. The sensor module 130 may be prepared in the state in which one endof the connection unit is connected to the circuit board 120 of thesensor module 130.

Thereinafter, the sensor module 130 is coupled to one side of thehydraulic block 200 while the connection unit connected to the sensormodule 130 is fitted into the through-hole 210 of the hydraulic block200.

As such, when the sensor module 130 is coupled to one side of thehydraulic block 200, the ECU 300 may be coupled to the other side of thehydraulic block 200 opposite to the sensor module 130, together with thehousing. In this case, the connection unit may be electrically connectedto a terminal provided in the ECU 300.

FIGS. 4 and 5 illustrate the state in which the sensor module is coupledthrough the connection unit when viewed from the front and the rear.

When the sensor module 130 is connected to the ECU 300, the connectionunit is penetrated and connected to the hydraulic block 200. Thus, sincethe connection unit is not exposed to the outside of the hydraulic block200, the connection unit can be conveniently arranged withoutinterfering with peripheral parts.

FIG. 6 is a flowchart illustrating a method of operating an electronicbrake system according to an embodiment of the disclosed technology.

As illustrated in FIG. 6, the embodiment of the disclosed technology mayprovide a method of operating an electronic brake system using anintegrated sensor. The method of operating an electronic brake systemwhich includes a circuit board 120 configured such that a pedal sensormodule for sensing a linear displacement of a pedal is mounted on oneside of the circuit board and a motor sensor module for sensing arotation angle displacement of a motor is mounted on the circuit board,may include a step (S10) of sensing a variation of a magnetic fieldgenerated by a magnet 133 moved along with movement of an input rod 131,a step (S20) of determining a movement distance of the pedal, based onthe intensity and direction of the magnetic field, a step (S30) ofsensing a position of the motor, and a step (S40) of controllingrotation of the motor corresponding to the movement distance of thepedal.

Accordingly, the disclosed technology may be used to provide a methodcapable of improving the safety of the system by mounting respectivesensors, which sense the displacement of the pedal and the position ofthe motor, as a single module.

Through such a method, it is possible to measure the rotation of themotor without a separate magnet for detecting the displacement of themotor.

In addition, the method may further include a step of determining arotation displacement of the motor, based on the rotation of the motor.

Furthermore, the method may further include a step of responding to amagnetic field having a directional component in the x-z plane or y-zplane perpendicular to the circuit board 120 to sense a variation of themagnetic field, and a step of generating an x-z angle signal or a y-zangle signal indicative of the angle of the directional component of themagnetic field from information about the variation of the magneticfield.

Since the pedal displacement sensing and the motor rotor sensing areperformed by the integrated sensor module 130 in the method of thedisclosed technology, it is possible to realize a fast response speedand reduce an influence of surrounding disturbance, compared to existingmethods.

In accordance with the disclosed technology, a connection unit forconnecting a sensor unit to a main circuit board is connected through athrough-hole of a hydraulic block by integrating an existing pedaldisplacement sensor with an existing motor rotor displacement sensor.Therefore, it is possible to prevent the connection unit frominterfering with other parts provided in the vicinity of the hydraulicblock, and to perform an assembly work.

In addition, since the connection unit is integrally provided in thesensor unit, it is possible to reduce the number of parts, and thus toreduce assembly processes and costs of products.

While the disclosed technology has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made.

What is claimed is:
 1. An electronic brake system for a vehicle using an integrated sensor, comprising: a hydraulic block configured to distribute and supply a fluid to a wheel brake, and having a through-hole penetrated at both sides thereof; a sensor module installed at one side of the hydraulic block having the through-hole, for sensing a linear displacement of a brake pedal and a position of a motor; and an electronic control unit installed to a side of the hydraulic block opposite to the sensor module, in order to determine a movement distance of the pedal, based on the linear displacement of the pedal sensed by the sensor module, and control rotation of the motor depending on the linear displacement of the pedal.
 2. The electronic brake system according to claim 1, wherein the sensor module comprises: a sensor housing coupled to the through-hole of the hydraulic block, and having a through-hole penetrated at both sides thereof; a circuit board installed at one side of the sensor housing and having a through-hole penetrated at both sides thereof, a sensing-related electric part being mounted on the circuit board; a pedal sensor module mounted at one side of the circuit board, in order to sense a magnetic field variation depending on movement of the pedal, and transfer information about the sensed magnetic field variation to the electronic control unit; and a motor sensor module mounted at one side of the circuit board, in order to sense an induced current generated by rotation of a rotor, and transfer information about the sensed induced current to the electronic control unit.
 3. The electronic brake system according to claim 2, further comprising a connection unit electrically connecting the sensor module to the electronic control unit through the through-hole of the hydraulic block while one end of the connection unit is fixed to the sensor module.
 4. The electronic brake system according to claim 3, wherein the pedal sensor module comprises: an input rod connected to the connection unit so as to be moved depending on movement of the pedal; a magnet provided at one end of the input rod so as to be moved depending on movement of the input rod; and a sensor unit configured to sense a magnetic field variation depending on movement of a magnetic substance, and transfer the sensed magnetic field variation to the electronic control unit.
 5. The electronic brake system according to claim 4, wherein: the sensor unit is installed at one side of the circuit board; and the magnet is disposed above the sensor unit so as to be spaced apart from the sensor unit.
 6. The electronic brake system according to claim 4, wherein the sensor unit is one of a Hall device, a reed switch, an AMR (Anisotropic Magneto-Resistive) sensor, and a GMR (Giant Magneto-Resistive) sensor.
 7. The electronic brake system according to claim 4, wherein: the sensor unit responds to a magnetic field having a directional component in an x-z plane or a y-z plane perpendicular to the circuit board to sense a variation of the magnetic field; and the electronic control unit generates an x-z angle signal or a y-z angle signal indicative of an angle of the directional component of the magnetic field from information about the variation of the magnetic field.
 8. The electronic brake system according to claim 2, wherein the motor sensor module comprises: a coil in which an induced current is generated by movement of the motor rotor; and a current sensor configured to sense the induced current in the coil and transfer a value of the sensed induced current to the electronic control unit.
 9. The electronic brake system according to claim 8, wherein the coil comprises: a first coil in which a magnetic flux is formed by electric energy generated by rotation of the motor; and a second coil configured of a pair of coils connected to each other while an induced current is generated according to the magnetic flux in the first coil.
 10. The electronic brake system according to claim 9, wherein the electronic control unit determines an rpm of the motor, based on a rotation angle displacement of the motor.
 11. A method of operating an electronic brake system for a vehicle, including a circuit board configured such that a pedal sensor module for sensing a linear displacement of a pedal is mounted on one side of the circuit board and a motor sensor module for sensing a rotation angle displacement of a motor is mounted on the circuit board, using an integrated sensor, the method comprising: sensing a variation of a magnetic field generated by a magnet moved along with movement of an input rod; determining a movement distance of the pedal, based on an intensity and a direction of the magnetic field; sensing a position of the motor; and controlling rotation of the motor corresponding to the movement distance of the pedal.
 12. The method according to claim 11, further comprising determining a rotation displacement of the motor, based on the rotation of the motor.
 13. The method according to claim 12, further comprising: responding to a magnetic field having a directional component in an x-z plane or a y-z plane perpendicular to the circuit board to sense a variation of the magnetic field; and generating an x-z angle signal or a y-z angle signal indicative of an angle of the directional component of the magnetic field from information about the variation of the magnetic field.
 14. The method according to claim 11, wherein: in the sensing a position of the motor, the position of the motor is sensed through an induced current generated in a coil by movement of a motor rotor; and the coil comprises a first coil in which a magnetic flux is formed by electric energy generated by the rotation of the motor, and a second coil configured of a pair of coils connected to each other while an induced current is generated according to the magnetic flux in the first coil. 